A known technique for retarding an internal combustion comprises augmenting engine back-pressure. One way of doing this comprises restricting the exhaust gas flow from the engine. In a conventional camshaft engine, a valve that is disposed in the exhaust system, sometimes called an exhaust brake, can be operated to restrict the exhaust gas flow. In an engine that has variable valve actuation, the individual cylinder exhaust valves may be actuated in a manner that creates the desired restriction.
Certain diesel engines have fuel injection systems that utilize hydraulic fluid under pressure to force fuel into engine combustion chambers. The hydraulic fluid is supplied to a respective fuel injector at each engine cylinder. When a valve mechanism of a fuel injector is operated by an electric signal from an engine control system to inject fuel into the respective cylinder, the hydraulic fluid is allowed to act on a piston in the fuel injector to force a charge of fuel into the respective combustion chamber.